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Report: The Global Threat to Manta and Mobula Rays

Time is running out for mantas and mobulas

Manta and mobula populations (collectively, “mobulids”) don’t stand a chance against the onslaught of targeted fishing. Mobulids are very slow to mature – 8-10 years or more – and reproduce very slowly – on average one pup every 2-5 years. By comparison, the Great White Shark, a highly vulnerable species protected under Appendix II of CITES, may produce more young in one litter than a manta ray will in her entire lifetime.

In just a few short years, regional populations of mobulids have already been severely depleted and in some cases have largely disappeared.

While conducting a decade long investigation into the global shark fin trade, we began to notice a heart-wrenching trend in fish markets around the world – manta and mobula rays being sold for their meat and gill-rakers. In fact, in just one small fishing port in Indonesia, we documented up to a dozen mantas and mobulas lined up in the street. Repeat visits to this market revealed the same grizzly scene, time and time again. Similarly, in a fishing port in Sri Lanka, we counted 23 dead mobula rays in one morning, and according to the fishermen, mobula rays were landed here every day. We had never seen so many mobula rays in one place – either dead or alive. Further investigation led us to the traders where we discovered a row of sacks, each containing gill-rakers from about 100 manta and mobula rays. On the roof, we were shown the gill-rakers from a recent catch of hundreds of mobulas being dried prior to export. We also learned that often manta and mobula cartilage is used as filler in shark fin soup.

We had to know what was driving fishermen to target mantas and mobulas. Our research and discussions with marine scientists and traders revealed that the gill-rakers were increasingly being used in Chinese medicine as a health tonic, driven by a belief that gill-rakers cool the blood. Demand for gill rakers now reached across oceans, giving rise to unsustainable manta ray fisheries throughout the range of these majestic creatures.

Through our research, we have learned that demand for manta and mobula gill-rakers is rapidly approaching a critical inflection point. Whereas the shark fin trade has sadly become deeply entrenched, both culturally and economically, there maybe time to intercept and head-off the gill-raker trade before it becomes completely entrenched. With this realization, we have set out to tell this story in the hopes of driving real change before it is too late.